The present invention relates to a percutaneous catheterization system which is universally compatible with standard connectors, and, more particularly, to a system which facilitates the frequent replacement of the catheter tubing which is necessary in such catheterization procedures.
It is very common in the treatment of hospitalized patients to utilize intravenous (IV) catheters to introduce certain fluids directly into the bloodstream of the patient. Such procedures are also becoming more common outside of the hospital as the high cost of hospital medical care has brought about the advent of neighborhood out-patient clinics and home health care.
In IV catheterization, a supply of fluid is maintained in a container which is located at a height higher than the patient. The catheter tubing flows from the supply container to the location of introduction into the patient where it is attached to a catheter. This location is typically the back of the patient's hand or a vessel on the inside of the arm. Typically, a needle or other stylet is first introduced through the cannula portion of the catheter and into the skin of the patient at the desired location, and then removed after the cannula is inserted into the skin. The fluid then flows directly into the blood vessel of the patient by gravity, or, if necessary, by the pressure generated by the head of the fluid above the height of the patient.
In common practice, the catheter is maintained in place on the skin of the patient by the use of adhesive or surgical tape. Likewise, the connection between the tubing and the catheter is also maintained by use of tape. In addition, a safety loop is typically formed in the tubing so that any tension applied to the tubing is not passed directly to the cannula of the catheter but is taken up in the slack of the safety loop. This loop is also typically taped loosely to the skin of the patient. This entire taping procedure takes several minutes of the valuable time of health practitioners performing this procedure.
IV catheterization is frequently maintained for several days, depending upon the condition of the patient. This longevity requirement gives rise to several problems associated with IV catheters. For example, the catheter tubing is generally replaced every 24 to 48 hours in order to maintain the sterility of the fluid and the free-flow of the fluid through the tubing. Thus, a health practitioner is often called upon to frequently change the tubing and to retape the connection. Furthermore, the taping of the catheter to the skin of the patient often covers the location of insertion of the cannula. Thus, the tape must be removed in order to inspect the insertion location for inflammation or infection and a complete taping procedure again be initiated. In short, a great deal of valuable time of the health practitioner is used in applying significant amounts of surgical tape to IV catheters. Further, the frequent application and removal of surgical tape often results in the excoriation of the skin of the patient in the area of the insertion.
A number of catheterization systems have recently been developed which improve the stabilization of the catheter system and/or obviate the need for frequent application and removal of surgical tape during IV tubing changes. One such system is shown in U.S. Pat. No. 4,250,880, wherein a disposable catheter stabilizing fitting comprising a catheter hub-retaining cradle is attached to a laminar base, the base having an adhesive undersurface for attachment to the patient. The cradle is designed to hold the catheter hub at a suitable angle to avoid bending or crimping of the catheter so as to facilitate access to the point of catheter insertion to the skin, however, the device is still required to be secured and stabilized by being overlaid with adhesive tape.
Another catheterization system is described in U.S. Pat. No. 4,711,636, comprising a specially designed cannula which is attachable via an adaptor to an IV tubing. The cannula is removably attached to a base, which is adhesively attachable to the skin of a patient. The cannula is adapted to be secured to the base portion in a snap-fit engagement so as to obviate the necessity for the time consuming application of surgical tape or other apparatus to stabilize the catheter, as previously mentioned. However, this cannula is specially adapted for attachment to the base portion of the assembly, and therefore, cannot be used with conventional luer-type connectors on conventional cannula apparatus.
The above-referenced pending parent patent application discloses a system which represents an improvement over the apparatus shown in above-mentioned U.S. Pat. No. 4,711,636 in that the system in the pending application can be used with conventional luer-type connectors on conventional cannula apparatus. However, one of the difficulties of utilizing an adaptor which can attach to conventional connectors is that there are some dimensional variances in conventional connectors. Typically, such connectors employ a tapered hub with an outwardly extending flange on the larger end. That pending application employs a retention latch which is manually movable to latch onto the flange on the end of the connector, and thus securely hold the connector with respect to the adaptor. This works quite well with most standard-type connectors, but connectors having slight dimensional variations do not fit so well because there is no means in the latch to accommodate such variations. Thus, a need exists for a latch that can handle such variations.
The manually operated mechanism for opening the latch in the above-referenced application and in the above-mentioned U.S. Pat. No. 4,711,636 extends outwardly away from the patient skin to facilitate operation. While the device is relatively small, it does extend outwardly enough such that it can interfere in taping or other medical procedures, or can interfere with patient movement. Thus it is desirable that a system be provided which improves that aspect.
Another type of standard IV connection involves the use of "injection sites." Although such sites may occur at various locations in IV catheterization systems, one common location is where the catheter is directly inserted into the patient's vein. This injection site connection comprises a cylindrical tube mounted on the end of the catheter with a rubber septum or "buff cap" stretched over or inserted within the open end of the tube. Originally, this type of connection was intended to facilitate manual injections. That is, the nurse can insert a needle through the rubber material of the septum and into the lumen on the other side thereof in order to cause medication to enter the patient. Once the needle is withdrawn, the rubber material of the septum closes the puncture area and seals the lumen. In addition to manual injections, however, this type of septum connector can be left in place in order to permit secondary attachments for IV purposes. The top surface of the septum can be easily cleaned and sterilized with an alcohol-saturated pad. Thus, this type of septum or buff cap connection is an alternative to a catheterization system utilizing a luer lock or hub on the end of the catheter. In the IV context, the septum connection is made up only by the insertion of a needle attached to the end of the IV line which is inserted through the rubber material of the septum.
However, along with the convenience provided by this septum-type connection, a number of problems have also arisen. First, the mechanical security of the connection of a needle inserted through rubber is obviously very poor. This problem is particularly aggravated by the duration of the connection. With the advent of long-term infusion, which has replaced manual injections for many applications, the needle/septum connection remains in use for many hours or days. Furthermore, this type of connection is frequently used in the home healthcare context. Because the patient is often ambulatory, the connection frequently disengages. As a consequence, nurses typically try to tape the connection together. However, this procedure takes extra time and does not protect the connection site from contamination. Also, with more frequent use of IV therapy, nurses are exposed many times each day to sharp needles. This type of septum connection increases the risk of accidental self-injection. Because many of the drugs contained in the IV solution are potent and toxic, this may be a very significant risk to a nurse using a septum connection.
Previous devices have not adequately addressed these problems. Most manufacturers have provided two customized adapters in order to avoid the above problems presented by the septum connection. For example, one component would comprise a special device incorporating the rubber cap and a second customized device incorporates the IV needle. Thus, standard septum connectors cannot be utilized. Furthermore, connector components are not interchangeable with other manufactured components. This two-piece customized approach also increases the expense associated with this form of IV therapy. Furthermore, previous devices do not provide adequate protection against accidental self-injection. The customized components are often bulky and prevent injections close to the patient's skin. Furthermore, these devices do not provide prevention against contamination of the septum surface after the connection is made. In other words, nurses still find it necessary to tape the connection, increasing the expense and time consumption of this procedure.